A serial type ink jet recording apparatus has long been known. It comprises: an ink jet head which records by ejecting ink; and a replaceable ink cartridge which stores recording ink. The ink jet head and ink cartridge are mounted on the carriage of the recording apparatus. The recording apparatus records by shuttling the carriage in a manner to scan recording medium, in the direction perpendicular to the direction in which recording medium is discharged. This recording method makes it possible to replace the ink cartridge without replacing the ink jet head, which is rather expensive. Therefore, it reduces recording cost.
This recording method, however, has its own problem. That is, in the case of this recording method, as the ink jet head is reciprocally moved across the surface of the recording medium, the ink cartridge is also reciprocally moved along with the ink jet head. Therefore, the recording apparatus is required to large enough to afford an internal space in which the carriage holding both the ink jet head and ink cartridge can be shuttled. This makes it difficult to reduce the size of an ink jet recording apparatus. Further, if a large ink cartridge is employed, not only must the carriage driving portion of the recording apparatus be increased in size in order to stabilize the speed at which the carriage is shuttled, but also, the ranges necessary to accelerate or decelerate the carriage must be increased in length. In other words, the employment of this recording method contradicts the effort to reduce the size of a recording apparatus.
As a solution to the above described problem, there have been proposed a few ink jet recording apparatuses in which the ink cartridge is not mounted on the carriage. For example, there has been proposed a recording apparatus in which a large ink cartridge is positioned away from the carriage, and its head is connected to the ink cartridge with the use of a tube. There has been also proposed a recording apparatus in which its head is intermittently supplied with ink, that is, it is supplied as necessary; more specifically, the ink cartridge and ink jet head are directly connected to each other to supply the ink jet head with ink, only as the amount of the ink remaining in the ink jet head falls below a predetermined value (this type of recording apparatus hereinafter may be referred to as pit-in type, for convenience). Referring to FIG. 13, as an example of the pit-in type recording apparatus, there is a recording apparatus structured so that as the carriage 1012 reaches the pit, the entirety of the connective portion 1010 is pulled out of the ink cartridge and moved to be connected to the head (Japanese Laid-open Patent Application (corresponding to U.S. Pat. No. 6,030,073).
In the case of the tube type recording apparatus in accordance with the prior art, the recording apparatus requires a mechanism and/or space for preventing the tube from being critically bent. Further, a larger motor is necessary to provide the force for moving the combination of the carriage and the tube, that is, the combination of the weights of the carriage and tube, inclusive of the ink therein. Thus, it is difficult to reduce the size of an ink jet recording apparatus.
On the other hand, in the case of the pit-in type recording apparatus, the connective portion of an ink cartridge must be precisely moved so that the connective portion of the ink cartridge and the counterpart of the head remain parallel to each other while they are moved relative to each other. This complicates the mechanism for driving the connective portions. Further, the connective portions must be made rigid enough to prevent the connective portions from deforming due to the load to which they are subjected when they are connected to each other. These requirements makes it difficult to reduce the size of the pit-in type recording apparatus. Moreover, if the pit-in type ink jet recording apparatus reduces in the accuracy with which the connective portion of an ink cartridge is moved relative to the ink jet head of the recording apparatus main assembly so that it remains parallel to the counterpart of the recording head the apparatus, it reduces in the reliability in terms of the connection between its ink jet head and an ink container; in other words, ink leaks from the joint and/or air is suctioned into the ink supply line, causing thereby the ink jet head to be insufficiently supplied with ink. Further, the pit-in type ink jet recording apparatus requires a relatively large amount of mechanical force to drive the complicated mechanism for moving the connective portions, being therefore relatively large in electrical power consumption, which in turn makes it difficult to operate the pit-in type recording apparatus for a long time using only the internal power source; in reality, the pit-in type ink jet recording apparatus requires an external power supply. This makes it difficult to provide a small and light portable ink jet recording apparatus.